[pr65536]

We are currently trying to measure pH levels on the (wet) surface of metals as part of a study about corrosion.
The surface may have a non-conductive protective layer.

- is it feasible to measure pH on a planar surface (dry or wet)? Which kind of sensor probe can be used for this task?
- which order of magnitude will be the measure? (precision of the sensor)

Any advice would be greatly appreciated!

[Arkcon]

Generally, you can only get an accurate pH value from a solution, not a damp,coated surface.  So your plan is nearly dead in the water.  There are probes for sale that will take a reading from a damp surface, but they're dubious to begin with, so whatever precision or accuracy they offer, you just have to accept.

[pr65536]

Dear Arkcon,
thank you for your answer. It made clear a couple of things. We have probably to go back to our draw table...
Thanks